The FB114 05 25 Grey Double Ply Black Poly R-4.2 by Mueller Streamline is designed for effective insulation and durability. This product features a double ply construction, providing an R-4.2 thermal resistance rating, making it suitable for various HVAC applications. Measuring 5 inches in diameter, it ensures efficient temperature control. The grey poly finish enhances its aesthetic appeal while offering protection against environmental factors. This lightweight insulation is easy to install and complies with industry standards, ensuring reliability and efficiency in energy savings.